Prevention of gastrointestinal injury by using glutamine in cardiac surgery

A pilot double-blind, placebo-controlled, randomized study The aim of this study was to evaluate the efficiency of perioperative administration of glutamine to preserve intestinal integrity in patients undergoing cardiac surgery. 24 patients scheduled for elective coronary artery bypass surgery under cardiopulmonary bypass were included in this prospective, randomized, double-blind placebo controlled pilot study. 12 patients were randomized to receive glutamine (20% solution of N(2)-L-alanyl-L-glutamine) 0.4 g/kg a day, while the remaining 12 patients received an equivalent placebo dose (0.9% solution of NaCl). Infusion of glutamine/placebo was started after the induction of anesthesia and was continued for 24 hours. The primary end-point was dynamics of plasma concentration of a specific marker of intestinal damage, intestinal fatty acid binding protein (I-FABP). The secondary end-points were liver fatty acid binding protein (L-FABP), alpha glutathione s-transferase (aGST), heat shock protein 70 (HSP 70). There were no between-group differences of all the studied biochemical parameters at any stage of the study. Plasma I-FABP levels (median [25-75 percentile]) were markedly elevated during CPB and remained the same postoperatively: 962 (577-2 067) and 883 (444-1 625) μг/ml 5 min after un-clamping of aorta, 2203 (888-3 429) and 1 560 (506-2 657) μг/ml 2 hours post-bypass, 897 (555-1 424) and 794 (505-951) μг/ml 6 hours post-bypass in the GLN and control groups respectively. Perioperative administration of glutamine in dose of 0.4 g/kg a day does not appear to preserve intestinal integrity in low risk cardiac surgery patients.